Conventionally, a three-terminal capacitor, as shown in an equivalent circuit in FIG. 12, is so constructed that one of two electrodes 1 provided opposite to each other at both sides of a dielectric is connected to input-output lead terminals 2 and 3, the other to a lead terminal 4, the input-output terminals 2 and 3 being connected in series with the circuit, the terminal 4 being earthed. Accordingly, when a signal is input to the terminal 2 and output from that 3, noises contained in the signal are directed to the earth through the ground terminal 4.
The three-terminal capacitor, which is thus remarkably effective in elimination of noise, is often used for the input-output unit of the computer.
The conventional three-terminal capacitor, however, as shown in FIGS. 13 and 14, is formed in a discrete part of a capacitor body 5 independently molded of resin, from which input-output terminals 2 and 3 and an earth terminal 4 extend respectively, Hence, the three-terminal capacitor, when mounted on a circuit substrate, requires a large mounting gap, so that a mounting area for the three-terminal capacitor is too larger for high density of the circuit substrate and an input-output connector, thereby creating the problem in that the three-terminal capacitor is hard to mount near the input-output connector. Moreover, the same three-terminal capacitors must be mounted on every circuit, thereby creating the problem in that the mounting work is complicated and the efficiency is reduced.